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    Cam timing problem

    Ok... bear with me here, as I try to explain something that would take a couple seconds to explain in person... was going to take pictures, but I doubt you'd be able to see the problem...

    So after putting new pistons in, I'm trying to get the heads together, and time up the cams. Chain tensioners are pinned.

    Starting with the front cylinder, spin crank counter clockwise to the FT mark, place cam lobes down. If I look at the cam gear marks, they don't line up perfectly with the head. One side is up a bit. If I skip a tooth, then the other side is up a bit... like it needs a 1/2 tooth!

    Same results with the rear cylinder once I spin the crank counter clockwise to RT.

    There is a F mark on the crank just before FT and RT show in the sight window. If I spin the crank to the F mark just before the FT mark, I am able to set the cam gear so the marks are perfectly inline with the head. Same result using the F before the RT mark. I doubt that this is what I should be doing... but at least there are no clearance problems with pistons and valves. I suspect ignition timing would now be off.

    Seems to me that the FT and RT marks, aren't as accurate as they could be.

    Can anyone give me some guidance?
    Thanks for any help!
    Bill

    #2
    Set them to whichever position puts the cam sprocket bolt line most closely to 90 degrees from the valve cover surface. (make sense?)
    J.D. Hord
    Keeper of Engine Nomenclature, 9th Order

    Comment


      #3
      Thanks, I was trying to do that as well, but it seems that for each cam there are two positions that are equally close to 90 degrees... There both so close that skipping the chain to the next tooth just makes it off by the same amount, but on the opposite side of 90.
      It's like I can only get the bolt hole to either 88 degrees, or 92.
      Going to have another crack at it today... Fresh look and all!
      What are the F marks for anyway, before FT and RT?

      Thanks
      Bill

      Comment


        #4
        Ok... Took another look today and looks like I've got it. I paid no attention to the timing marks on the sprocket and made sure the bolt hole was at 90 degrees... Even used a square to make sure I got it as close to 90 as I could! Hehe
        I would expect that chain wear was causing my problem... Looks like it's all fixed up now though.
        If I had more than an hour at a time to work on it, I'd be set!
        Thanks for your help J.D.

        Bill

        Comment


          #5
          Good to hear you got it. (but it's an example why I normally use adjustable cam sprockets and time things in pefectly with a degree wheel)

          The FT mark is obviously Front TDC. The F mark is the minimum ignition advance mark. The other marks are maximum advance.
          J.D. Hord
          Keeper of Engine Nomenclature, 9th Order

          Comment


            #6
            Originally Posted by Hordpower
            Good to hear you got it. (but it's an example why I normally use adjustable cam sprockets and time things in pefectly with a degree wheel)

            The FT mark is obviously Front TDC. The F mark is the minimum ignition advance mark. The other marks are maximum advance.

            hmm. i wonder if my comp cams degree wheel will fit on a hawk.. lol. is there a more "motorcycle size" degree wheel im goign to need?

            at some point, i want to build a hawk motor.. REALLY build one... and when it comes to building a motor, ive always believed that timing the valvetrain with a degree wheel and checking it is EXTREMELY important... dont just "line up the dots" but CHECK it.

            Comment


              #7
              Any old degree wheel will work, bigger the better. 99% of the engines I send out of here have the cams degreed, just part of the process.
              J.D. Hord
              Keeper of Engine Nomenclature, 9th Order

              Comment


                #8
                You must have to remove the side engine cover to attach it do you?
                Bill

                Comment


                  #9
                  degree the cams with a degree wheel was a nightmare. I think it took me 3-4 hours to figure out advancing X8 cams 2deg. Matt Stone provided me the indicator for finding the TDC of the piston and the indicator the finding Top of the cams. This - this finds the TDC of the piston. This - this finds the top center of the cam. + 2 deg for the advance. No wait. Yea. Ah shoot. Wait, I think I got. Bike has not blown up yet.

                  Come to find out I was 4 deg retarded from 0. Overall I was 6 deg from 2 deg advanced. I think I made it more difficult than it actually is.

                  JD you giving a class anytime soon. Sign me up.
                  Gino
                  Chain Roller

                  NEVER UNDERESTIMATE THE PREDICTABILITY OF STUPIDITY

                  2012 CCS LRRS ULSB Champion
                  2012 CCS LRRS P89 Champion
                  2008 CCS ULSB National Champion
                  LRRS HAWK GT Racer CCS Expert #929
                  ECK RACING

                  Comment


                    #10
                    Well I hate to tell you Gino, but the Hawk has about the easiest cams to degree you could ever hope for. My advice would be to stay away from the Testastretta Ducatis if the hawk gave you trouble.
                    J.D. Hord
                    Keeper of Engine Nomenclature, 9th Order

                    Comment


                      #11
                      its not too hard to degree cams..

                      if you say what part is confusing you, maybe i can help explain it?

                      Comment


                        #12
                        heres a basic howto.. i remember reading this back in high school.. LOL

                        http://www.hotrod.com/techarticles/e...cam/index.html

                        yes, its for cars.. but the principle is exactly the same. only diff is you're going to do it twice. (once for the front, once for the back)

                        Comment


                          #13
                          First time or the unknown is always seems bigger/scary than it really is.
                          Gino
                          Chain Roller

                          NEVER UNDERESTIMATE THE PREDICTABILITY OF STUPIDITY

                          2012 CCS LRRS ULSB Champion
                          2012 CCS LRRS P89 Champion
                          2008 CCS ULSB National Champion
                          LRRS HAWK GT Racer CCS Expert #929
                          ECK RACING

                          Comment


                            #14
                            Just razzin' ya... Next time will be a bunch easier, and then before you know it you'll be advancing the cam on your lawn mower, etc.
                            J.D. Hord
                            Keeper of Engine Nomenclature, 9th Order

                            Comment


                              #15
                              Originally Posted by Hordpower
                              Just razzin' ya... Next time will be a bunch easier, and then before you know it you'll be advancing the cam on your lawn mower, etc.
                              you know.. i bet one of thoes Jr Dragster cams would work great in my lawn mower.... hmmmmmmm

                              Comment

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